Assessing the role of filler atoms in skutterudites and synthesis and characterization of new filled skutterudites

Publication Year:
2006
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Downloads 350
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Repository URL:
https://scholarcommons.usf.edu/etd/2526
Author(s):
Fowler, Grant E
Tags:
Skutterudites; Thermal conductivity; Physics; Phonons; Thermoelectrics
thesis / dissertation description
For the past decade interest in skutterudites has been significant as a potentially viable material for thermoelectrics. One way to improve the effectiveness of these materials is to lower their thermal conductivity. Lattice thermal conductivity of a series of La- and Yb-filled skutterudite antimonides (with varying filling fraction) has been modeled with different phonon scattering parameters using the debye approximation. It was found that filler atoms both increase point defect scattering and resonance scattering. Subsequently, the thermal conductivity of partially-filled skutterudites AxCo4Sb12, where A = La, Eu and Yb, is analyzed using the Debye model in order to correlate the data with the type of filler atom in evaluating the role of the filler atom in affecting the thermal conductivity. Partial void filling has resulted in relatively high thermoelectric figures of merit at moderately high temperatures. This idea is extended as new materials were synthesized with the intention of filling the voids in the CoGe1.5Se1.5 skutterudite, and analyzing the transport of these novel materials. Results of the analysis of this material are interesting and may indicate an amorphous phase of skutterudite present. Further work is needed to explore fully the implications of this new skutterudite and to fully understand its properties.